Light pipe technology is a robust and inexpensive method for bringing light to the exterior of products for the purposes of communicating device status, or other important information to a user. Generally, a light pipe is used in situations where physical restrictions (e.g., lack of space, high component density), safety concerns (such as component accessibility to the end user, fragile bulbs, heat buildup), or other factors prevent the light-emitting component from being mounted in a way that provides direct visibility. Light pipes are often rendered as round-cross-section or rectangular-cross-section clear plastic structures, where the objective end is placed flush with, or close to, the light-emitting component. The viewed end is brought to the exterior of a product for viewing by an end user, and is often “frosted” or diffused to increase visibility.
Certain applications require a light pipe to be used where the light-emitting component is relatively far from the exterior of the product. In such cases, the length of a traditional light pipe might reduce by attenuation the amount of visible light available at the outside of the product to such an extent that the light signal essentially becomes non-existent. One existing solution for long-run light pipes (e.g., greater than five inches) is to utilize fiber optic or other glass-based technology. These solutions are expensive, however, due to the fragility and difficulty of handling glass or other crystalline materials. Another option is to use a step index or gradient index light pipe to maintain the light within the pipe over a relatively long distance. However, this solution also results in significantly increased costs.
Thus, a need remains in the art for further improvements to enhancing optical coupling between a light-emitting component and a relatively inexpensive light pipe.